Boat having movable keel device



March 12, 1963 E. G. POLLAK BOAT HAVING MOVABLE KEEL DEVICE 2Sheets-Sheet 1 Filed NOV. 6, 1961 4 INVEN/TDZ'IZM a @012 421 March 12,1963 E. G. POLLAK 3,080,845

BOAT HAVING MOVABLE KEEL DEVICE Filed NOV. 6, 1961 2 Sheets-Sheet 2United States Patent Office 3,080,845 Patented Mar. 12, 1963- 3,080,845BOAT HAVING MOVABLE KEEL DEVICE Edward George Pollak, Poppet-ell Road,Kittery, Maine Filed Nov. 6, 1961, Ser. No. 150,473 3 Claims. (Cl.114-140) This invention relates to a boat having a novel keel device.

One object of my invention is to provide a boat having, in addition tothe usual keel, a keel device having a flap that is movable to anyposition that is desirable.

Another object is to provide means whereby said keel device can beoperated by a person seated in a boat, to thereby move a keel fiap so asto acquire finer control over the movements of the boat when conditionsmake that desirable.

The foregoing and other objects which will appear as the nature of theinvention is better understood, may be accomplished by a construction,combination and arrangement of parts such as is disclosed by thedrawings. The nature of the invention is such as to render itsusceptible to various changes and modifications, and therefore, I amnot to be limited to the construction disclosed by the drawings nor tothe particular parts described in the specification; but am entitled toall such changes therefrom as fall within the scope of my claims.

In the drawings:

FIG. 1 is a diagrammatic, side elevational view of my boat.

FIG. 2 is a bottom plan view of said boat.

FIG. 3 is an enlarged, sectional view taken on the line 33 of FIG. 2.

FIG. 4 is a sectional view taken on the line 4-4 of} 1 16.3.

FIG. is a sectional View taken on the line 5-5 of FIG. 3.

As illustrated, I show a boat having a main body or h-ull 16 havingfloor timbers 11 and a keel timber 12 attached to said floor timbers. Arudder 13 is movably fastened to said hull by a well known shaft 14.

A well known keel 16 of the fin-type has a main body 17 that includes alower portion 18 of metal such as iron, bronze or lead. Said keel 16 isattached to said hull by a bolt 19 that extends through a said floortimber 11, k el timber 12 and said keel 16. This bolt 19' has a head 20countersunk in the lower end of said keel and at the upper end it has anut 22 and a bearing plate 24 outside a said floor timber 11 that holdsit in place. Another bolt 26 extends through another of said floortimbers, said keel timber and into said keel 16. This bolt 26 has a head27 extending into said keel metal portion 18 as shown, being retained asby a plug or plastic filler 28, and held in place by a nut 28a and abearing plate 29.

In addition to said fixed keel 16- I provide a movable keel device 30having a flap or keel after-portion 31 that is attached to a rotatablestock or shaft 32 by screws 34 or other pin members extending throughthe latter. Said shaft has a reduced upper portion 35, and it extendsthrough an opening in a said keel timber 12, and to the latter isattached hollow retaining means having a stufiing box 36, containingwaterproof packing 38 compressed by a gland nut 40. Screws 42 hold saidstuffing box 36 to said keel timber 12. Said shaft 32 movably extendsthrough said stufiing box and gland nut.

Said keel lower portion 18 has a lower, lateral extension 44 having arecess 46 that enables it to serve as a bearing member 48 for said shaft32. A metal strap or bearing 2.. member 50 is fastened by screws 52 tosaid keel main body 17 and it extends around said shaft 32 and enters arecess 54 in said keel flap 31, whereby said strap provides a bearingmember for said shaft.

Rotation of said keel device 30 may be controlled manually by a handleor tiller 55 shown broken away in said FIG. 4. This handle 55 is mountedon said shaft reduced portion 35, being attached thereto by a well knownshaft key 56 and retained thereon by a nut 60 screwthreadedly connectedto said shaft 32.

My invention is especially adapted for a sailboat. In sailing, the wind,by means of the sail or sails, exerts a large, lateral force upon thehull and keel, as well as a forward force, hence the boat does not movethrough the water in the direction of the center-line, whichis-indicated by the numeral 57 in said FIG. 2; but moves at an anglethereto. The angle between the direction of said motion and thedirection of the center-line of the vessel is termed angle of leeway andis dependent upon the size and shape of the underwater surface of thehull, keel and rudder. Said angle of leeway likewise is the angle ofattack of the water upon said keel.

Positioning of said keel flap 31 at an angle to said centerline 57alters the hydrodynamic characteristics of said keel and permits it tocounteract the lateral force of the wind at a smaller angle of attack orleeway, and increases speed through the water. Reduction of leeway ishighly desirable in sailing into the direction of the wind by theprocess of tacking inasmuch as the total distance that must be sailed isproportionate to the secant of the course angle made good relative tothe objective point, times the direct distance to the objective point. Areduction in course angle by reduction of leeway, or an increase inspeed, are the two factors which can reduce the time required by avessel to reach a destination lying upwind.

In said FIG. 4'the arrow 59 indicates the direction of water flowrelative to the vessel, the angle between said arrow 59, and thecenter-line 57, is the angle of attack or angle of leeway. The arrow 60indicates the general direction and relative magnitude of the forceexerted by the wind; and the arrow 61 indicates the general directionand relative magnitude of the force exerted by the keel; and the arrow62 indicates the direction and relative magnitude of the forcesrecognized as hydrodynamic resistance of the hull, keel, rudder andother underwater portions of the vessel.

What I claim is:

l. A boat comprising a hull, a rudder connected to said hull, a keelconnected to said h-ull, a keel device rearwardly of said keel andspaced forwardly from said rudder, said keel device having a rotatableshaft extending downwardly and adjacent said keel, only one flapattached to and movable with said shaft relative to said keel, and meansrotatably connecting said shaft to said hull.

2. A boat comprising a hull, a rudder connected to said hull, a keelconnected to said hull, a keel device rearwardly of said keel and spacedforwardly from said rudder, said keel device having a rotatable shaftextending downwardly and adjacent said keel, only one flap rearwardly ofsaid keel and attached to, extending parallel with, and

movable with said shaft relative to said keel, and means rotatablyconnecting said shaft to said hull, the longitudinal axis of said flapextending parallel with the longitudinal axis of said shaft.

3. A boat comprising a hull, a rudder connected to said hull, a keelconnected to said hull, and fixedly positioned longitudinally therewith,a keel device rearwardly of said keel and spaced forwardly from saidrudder, said keel device having a rotatable shaft extending downwardlyand adjacent said keel, only one flap attached to, and movable with saidshaft laterally relative to said keel, and means rotatably connectingsaid shaft to said hull, said rudder being positioned at a rear halfportion of said hull, said keel and keel device being positionedadjacent the midlength of said hull, said flap extending downwardlyparallel with said keel.

References Cited in the file of this patent UNITED STATES PATENTSStromborg Aug. 23, 1904 Hale Nov. 1, 1932 Paine July 25, 1939 ScottSept. 9, 1958

1. A BOAT COMPRISING A HULL, A RUDDER CONNECTED TO SAID HULL, A KEELCONNECTED TO SAID HULL, A KEEL DEVICE REARWARDLY OF SAID KEEL AND SPACEDFORWARDLY FROM SAID RUDDER, SAID KEEL DEVICE HAVING A ROTATABLE SHAFTEXTENDING DOWNWARDLY AND ADJACENT SAID KEEL, ONLY ONE FLAP ATTACHED TOAND MOVABLE WITH SAID SHAFT RELATIVE TO SAID KEEL, AND MEANS ROTATABLYCONNECTING SAID SHAFT TO SAID HULL.